An apparatus and a method for combustion of oil with the addition of water are known of WO95/23942, in which oil is introduced into a combustion chamber until an oil bath has formed, which is then preheated to a temperature between 250° C. and 350° C. Then water is sprayed onto the surface of the hot oil bath, which results in a flame eruption with the simultaneous supply of air into the combustion chamber. The level of the oil bath should not remain under a height of 3 to 4 mm during combustion in order to prevent an interruption of the combustion. The apparatus used to this purpose includes in general a combustion chamber in the form of a frustrum of a pyramid or a cone with lateral supply openings for oil and water from corresponding reservoirs. The oil bath is electrically heated. Air enters along with the water into the interior of the combustion chamber. The flame with a temperature of 1200° C. to 2000° C. is introduced into an oven via a cylindrical tube for heating purposes.
In this known method of combustion especially of waste oils the temperature gradient appearing in the oil bath in the direction to the bottom has proved to be disadvantageous, because the bottom temperature can be lower than the evaporation temperatures of heavy fractions in the waste oil the result of which is that the latter form a not completely burnable oil mass at the bottom of the combustion chamber. Injecting the oil via a nozzle is not practical, because residues and highly viscous components in the waste oil will lead to a clogging of the nozzles. Moreover the entire apparatus with its feeding and preheating means gets constructively complex. Because of the remaining residues the process control is hard to perform, especially when shutting down. Therefore the facility is not suited for a continuous operation.
From GB 765 197 an apparatus for the combustion of liquid and liquefiable fuels is known, which consists of a cylindrical combustion chamber with an adjacent fire space, which is open to the top. The liquid fuel is radially or tangentially introduced into the interior of the combustion chamber, and air is separately introduced tangentially, which the fuel is contacting the inner surface of the combustion chamber and is evaporated and burnt there. Temperatures appearing in the fire space are between 1500° C. and 1800° C. With incomplete combustion by reduced air supply the fuel is cracked with the aid of supplied vapour, whereby heavy oils are decomposed into lower hydrocarbons, hydrogen and carbon monoxide.
Also in this known combustion method the way of supply is technically demanding, and moreover the danger exists that in certain wall regions the temperature is not sufficient for evaporation of heavier waste oil fractions, which then gather at the bottom of the combustion chamber and form a non-burnable residue there. Water vapour is here not provided for the actual combustion but only for cracking of heavy oils.
In U.S. Pat. No. 4,069,005 the combustion of a water/fuel/air mixture in the presence of a metal catalyst (nickel) is proposed, wherein in the interior of the burner several stacked plates, which may also consist of the metal catalyst, can be disposed, to increase the efficiency of the resulting cracking. In the apparatus serving this purpose liquid fuels and water are respectively dropped upon the catalyst from above, the plates having been heated to a temperature above 800° C. in a preheating phase. The rising vapours are led along the metal catalysts, whereby easily burnable, gaseous hydrocarbons are generated by cracking, which burn in the further process, whereby combustion gases of 800° C. to 1000° C. are generated.
For the generation of a long flame for heating an industrial boiler in U.S. Pat. No. 3,804,579 oil and air are burnt together with water vapour, which is generated in a heat exchange coil by the flame. Here the extended flame burns at about 730° C.
Finally from DE 39 29 759 C2 a facility for burning waste oil products is known, in which the waste oils are mixed with a usual heating oil with a known smaller viscosity, such that an average product with constant viscosity is formed, which is then preheated and injected into a tank. On the opposite side of the tank input devices for air, water and common neutralizing agents are provided. For injecting the oil mixture air or water vapour is used. The control facility for the mixing ratio of the oils and the injection apparatus for the oil mixture with additional supply leads for air and neutralizing agents lead to a constructively complex facility, which is hard to control, and which cannot work efficiently, because apart from the actual combustion product of waste oil considerable amounts of normal heating oil have to be burned additionally, which largely limits the disposal capacity. The simple combustion tank cannot support the combustion process.
Flow bodies or baffle members are used in various technical fields for deflecting flows or influencing their dynamics. In combustion technology, for example, it is known to improve the distribution of a fuel mixture which is to be burned inside a reaction chamber by placing a deflector surface in the direction of flow of the mixture. A deflector surface of this kind is used herein as well as in WO99/24756 to deflect the mixture which is to be burned out of its original direction of influx and distribute it as symmetrically as possible inside the reaction chamber. This promotes mixing of the individual components of the fuel mixture and thus achieves fast and total combustion. In these embodiments the deflector surface has conical or pyramidal surfaces with an apex that points in the direction of the inflowing mixture.
One disadvantage of a deflector surface of this kind is that because of the deceleration of the components of the fuel mixture associated with the deflection and because of the partial reflection of these components back in the direction of the inflow openings, it is not possible to achieve the desired homogenous flow of the combustible mixture accelerating in the direction of the outlet opening of the reaction chamber.
Moreover, DE2153817OS discloses a burner for burning waste materials wherein the waste materials together with air supplied step by step enter a combustion chamber in which there is a so-called hot bulb. This hot bulb is conical in shape and is arranged with its tip pointing in the direction of the inflowing mixture which is to be burned and coaxially with the axis of the combustion chamber. This hot bulb is at a temperature of 1200 to 1400° C. and causes combustion of unburnt components of the waste material such as, for example, solid particles which are difficult to burn. This hot bulb may also be in the form of a ring.
A hot bulb of this kind according to DE2153817OS has a negative effect on the flow dynamics in the combustion chamber for the reasons mentioned above.